Enhanced In-Plane Thermoelectric Figure of Merit for p-Type Bi0.5Sb1.5Te3 Thin Films with Temperature Dependence Approaching 450 K

Abstract

Bi0.5Sb1.5Te3 (BST) materials are widely used p-type thermoelectric (TE) materials with high anisotropy. Thin-film-based TE materials are also highly useful for future TE devices. However, very limited information is available regarding the in-plane figure of merit (ZT) of BST thin films, including the in-plane thermal conductivity, Seebeck coefficient, and electrical conductivity of the film. This work examines the in-plane ZT properties of p-Bi0.5Sb1.5Te3 thin films prepared by radiofrequency sputtering at room temperature. Based on the measured thermoelectric properties including the in-plane thermal conductivity, Seebeck coefficient, and electrical conductivity, a maximum ZT value of 1.01 at 390 K was obtained for these annealed p-BST thin films.